From d3cc861d334c8b773c1b6c662ed9924c43cef009 Mon Sep 17 00:00:00 2001 From: mid-kid Date: Wed, 4 Apr 2018 22:26:07 +0200 Subject: Fix snake_case filenames Renamed a bunch of files, most of them one-off functions, to better fit the general snake_case naming scheme. Also renamed some awfully long filenames. --- engine/math/get_square_root.asm | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 engine/math/get_square_root.asm (limited to 'engine/math/get_square_root.asm') diff --git a/engine/math/get_square_root.asm b/engine/math/get_square_root.asm new file mode 100644 index 000000000..412fd04ff --- /dev/null +++ b/engine/math/get_square_root.asm @@ -0,0 +1,32 @@ +NUM_SQUARE_ROOTS EQU 255 + +GetSquareRoot: ; 13b87 +; Return the square root of de in b. + +; Rather than calculating the result, we take the index of the +; first value in a table of squares that isn't lower than de. + + ld hl, .Squares + ld b, 0 +.loop +; Make sure we don't go past the end of the table. + inc b + ld a, b + cp NUM_SQUARE_ROOTS + ret z + +; Iterate over the table until b**2 >= de. + ld a, [hli] + sub e + ld a, [hli] + sbc d + + jr c, .loop + ret + +.Squares: ; 13b98 +x = 1 +rept NUM_SQUARE_ROOTS + dw x * x +x = x + 1 +endr -- cgit v1.2.3